The long-range goals of the project remain essentially unchanged from previous years, that is, to extend our understanding of the psychophysical characteristics of responses to vibrotactile stimulation in humans within the context of the possible receptor/neural mechanisms that may underlie those characteristics. Beyond these fundamental and basic goals, and in the realm of application, information processing by cutaneous tactile systems may be utilized when the effectiveness of conventional channels is limited, as in high noise environments, when existing channels are overtaxed, or when existing channels suffer a sensory deficit. There still exist sizable gaps in our knowledge of the fundamental characteristics of the cutaneous sensory systems and that knowledge lags far behind the information that is available for the auditory and visual systems. The basic aim of the proposed research is to close these gaps. The experiments fall into five general problem areas: 1) spatiotemporal aspects of vibrotactile sensation, especially those relating to the development of tactile communication devices; 2) further exploration of parameters relating to the newly developed four-channel model of cutaneous mechanoreception at threshold; 3) suprathreshold levels of stimulation; 4) cross-modality interactions; and; 5) effects of peripheral neuropathies associated with carpal tunnel syndrome, vibration "white finger", and diabetes. The experiments are targeted on exploring the functional properties of both Pacinian and non-Pacinian receptor systems, within the context of the four-channel model.